一个等比数列的第三项为 1764，第二项与第三项的和为 3444。

求第 50 项。

Answer all questions. You should use a calculator where appropriate.

You must show all necessary working clearly; no marks will be given for unsupported answers from a calculator.

Give non-exact numerical answers correct to 3 significant figures, or 1 decimal place for angles in degrees, unless a different level of accuracy is specified in the question.

请回答所有题目。适当时应使用计算器。必须清楚展示所有必要的计算过程；仅给出计算器答案而没有过程，不予评分。除非题目另有精度要求，非精确数值答案保留 3 位有效数字，以度为单位的角度保留 1 位小数。

从第二、三项之和减去第三项，便得到第二项。两项相除得公比。

The second term is $3444-1764=1680$, so the ratio is $1764/1680=21/20$. The fiftieth term is $48$ steps after the second term, so it is

to three significant figures.